Javascript 使用javascript验证html中的输入文本字段

validation of input text field in html using javascript

提问by VinKrish

<script type='text/javascript'>   
function required()  
{
    var empt = document.forms["form1"]["Name"].value; 
    if (empt == "")  
    {  
        alert("Please input a Value");  
        return false;  
    }  
}  
</script> 

<form name="form1" method="" action="">
<input type="text" name="name" value="Name"/><br />
<input type="text" name="address line1" value="Address Line 1"/><br />

I have more than one input text field, each having their default value. Before I submit the form I have to verify whether all fields are filled. So far i got the javascript to check for null since different text boxes have different default value. How can I write a javascript to verify that user has entered data? I mean, the script must identify that input data is other than default and null.

我有多个输入文本字段，每个字段都有自己的默认值。在提交表单之前，我必须验证是否已填写所有字段。到目前为止，由于不同的文本框具有不同的默认值，我让 javascript 来检查 null。如何编写 javascript 来验证用户是否已输入数据？我的意思是，脚本必须确定输入数据不是默认值和空值。

采纳答案by Dzeimsas Zvirblis

If you are not using jQuery then I would simply write a validation method that you can be fired when the form is submitted. The method can validate the text fields to make sure that they are not empty or the default value. The method will return a bool value and if it is false you can fire off your alert and assign classes to highlight the fields that did not pass validation.

如果您不使用 jQuery，那么我将简单地编写一个验证方法，您可以在提交表单时触发该方法。该方法可以验证文本字段以确保它们不为空或默认值。该方法将返回一个 bool 值，如果它为 false，您可以触发警报并分配类以突出显示未通过验证的字段。

HTML:

HTML：

<form name="form1" method="" action="" onsubmit="return validateForm(this)">
<input type="text" name="name" value="Name"/><br />
<input type="text" name="addressLine01" value="Address Line 1"/><br />
<input type="submit"/>
</form>

JavaScript:

JavaScript：

function validateForm(form) {

    var nameField = form.name;
    var addressLine01 = form.addressLine01;

    if (isNotEmpty(nameField)) {
        if(isNotEmpty(addressLine01)) {
            return true;
        {
    {
    return false;
}

function isNotEmpty(field) {

    var fieldData = field.value;

    if (fieldData.length == 0 || fieldData == "" || fieldData == fieldData) {

        field.className = "FieldError"; //Classs to highlight error
        alert("Please correct the errors in order to continue.");
        return false;
    } else {

        field.className = "FieldOk"; //Resets field back to default
        return true; //Submits form
    }
}

The validateForm method assigns the elements you want to validate and then in this case calls the isNotEmpty method to validate if the field is empty or has not been changed from the default value. it continuously calls the inNotEmpty method until it returns a value of true or if the conditional fails for that field it will return false.

validateForm 方法分配您要验证的元素，然后在这种情况下调用 isNotEmpty 方法来验证该字段是否为空或未更改默认值。它不断调用 inNotEmpty 方法，直到它返回 true 值，或者如果该字段的条件失败，它将返回 false。

Give this a shot and let me know if it helps or if you have any questions. of course you can write additional custom methods to validate numbers only, email address, valid URL, etc.

试一试，让我知道它是否有帮助或您有任何问题。当然，您可以编写其他自定义方法来仅验证数字、电子邮件地址、有效 URL 等。

If you use jQuery at all I would look into trying out the jQuery Validation plug-in. I have been using it for my last few projects and it is pretty nice. Check it out if you get a chance. http://docs.jquery.com/Plugins/Validation

如果您完全使用 jQuery，我会考虑试用 jQuery 验证插件。我一直在我最近的几个项目中使用它，它非常好。有机会的话就去看看吧。http://docs.jquery.com/Plugins/Validation

回答by Hemangi

<form name="myForm" id="myForm" method="post" onsubmit="return validateForm();">
    First Name: <input type="text" id="name" /> <br />
    <span id="nameErrMsg" class="error"></span> <br />
    <!-- ... all your other stuff ... -->
</form>
  <p>
    1.word should be atleast 5 letter<br>
    2.No space should be encountered<br>
    3.No numbers and special characters allowed<br>
    4.letters can be repeated upto 3(eg: aa is allowed aaa is not allowed)
  </p>
  <button id="validateTestButton" value="Validate now" onclick="validateForm();">Validate now</button>


validateForm = function () {
    return checkName();
}

function checkName() {
    var x = document.myForm;
    var input = x.name.value;
    var errMsgHolder = document.getElementById('nameErrMsg');
    if (input.length < 5) {
        errMsgHolder.innerHTML =
            'Please enter a name with at least 5 letters';
        return false;
    } else if (!(/^\S{3,}$/.test(input))) {
        errMsgHolder.innerHTML =
            'Name cannot contain whitespace';
        return false;
    }else if(!(/^[a-zA-Z]+$/.test(input)))
    {
        errMsgHolder.innerHTML=
                'Only alphabets allowed'
    }
    else if(!(/^(?:(\w)(?!))+$/.test(input)))
    {
        errMsgHolder.innerHTML=
                'per 3 alphabets allowed'
    }
    else {
        errMsgHolder.innerHTML = '';
        return undefined;
    }       

}

.error {
color: #E00000;
 }

回答by Ravindra Bohra

<pre><form name="myform" action="saveNew" method="post" enctype="multipart/form-data">
    <input type="text"   id="name"   name="name" /> 
<input type="submit"/>
</form></pre>

<script language="JavaScript" type="text/javascript">
 var frmvalidator  = new Validator("myform");
    frmvalidator.EnableFocusOnError(false); 
    frmvalidator.EnableMsgsTogether(); 
    frmvalidator.addValidation("name","req","Plese Enter Name"); 

</script>




before using above code you have to add the gen_validatorv31.js js file

回答by Delino

For flexibility and other places you might want to validated. You can use the following function.

为了灵活性和其他您可能需要验证的地方。您可以使用以下功能。

`function validateOnlyTextField(element) {
    var str = element.value;
    if(!(/^[a-zA-Z, ]+$/.test(str))){
        // console.log('String contain number characters');
        str = str.substr(0,  str.length -1);
        element.value = str;
    }
}`

Then on your html section use the following event.

然后在您的 html 部分使用以下事件。

<input type="text" id="names" onkeyup="validateOnlyTextField(this)" />

<input type="text" id="names" onkeyup="validateOnlyTextField(this)" />

You can always reuse the function.

您可以随时重复使用该功能。

回答by AKHIL

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
        <title>Validation</title>
        <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
        <script type="text/javascript">
            var tags = document.getElementsByTagName("input");
            var radiotags = document.getElementsByName("gender");
            var compareValidator = ['compare'];
            var formtag = document.getElementsByTagName("form");
            function validation(){
                for(var i=0;i<tags.length;i++){
                    var tagid = tags[i].id;
                    var tagval = tags[i].value;
                    var tagtit = tags[i].title;
                    var tagclass = tags[i].className;
                    //Validation for Textbox Start
                    if(tags[i].type == "text"){
                        if(tagval == "" || tagval == null){
                            var lbl = $(tags[i]).prev().text();
                            lbl = lbl.replace(/ : /g,'')
                            //alert("Please Enter "+lbl);
                            $(".span"+tagid).remove();
                            $("#"+tagid).after("<span style='color:red;' class='span"+tagid+"'>Please Enter "+lbl+"</span>");
                            $("#"+tagid).focus();
                            //return false;
                        }
                        else if(tagval != "" || tagval != null){
                            $(".span"+tagid).remove();
                        }
                        //Validation for compare text in two text boxes Start
                        //put two tags with same class name and put class name in compareValidator.
                        for(var j=0;j<compareValidator.length;j++){
                            if((tagval != "") && (tagclass.indexOf(compareValidator[j]) != -1)){
                                if(($('.'+compareValidator[j]).first().val()) != ($('.'+compareValidator[j]).last().val())){
                                    $("."+compareValidator[j]+":last").after("<span style='color:red;' class='span"+tagid+"'>Invalid Text</span>");
                                    $("span").prev("span").remove();
                                    $("."+compareValidator[j]+":last").focus();
                                    //return false;
                                }
                            }
                        }
                        //Validation for compare text in two text boxes End
                        //Validation for Email Start
                        if((tagval != "") && (tagclass.indexOf('email') != -1)){
                        //enter class = email where you want to use email validator
                            var reg = /^\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/
                            if (reg.test(tagval)){
                                $(".span"+tagid).remove();
                                return true; 
                            }
                            else{
                                $(".span"+tagid).remove();
                                $("#"+tagid).after("<span style='color:red;' class='span"+tagid+"'>Email is Invalid</span>");
                                $("#"+tagid).focus();
                                return false;
                            }
                        }
                        //Validation for Email End
                    }
                    //Validation for Textbox End
                    //Validation for Radio Start
                    else if(tags[i].type == "radio"){
                    //enter class = gender where you want to use gender validator
                        if((radiotags[0].checked == false) && (radiotags[1].checked == false)){
                            $(".span"+tagid).remove();
                            //$("#"+tagid").after("<span style='color:red;' class='span"+tagid+"'>Please Select Your Gender </span>");
                            $(".gender:last").next().after("<span style='color:red;' class='span"+tagid+"'> Please Select Your Gender</span>");
                            $("#"+tagid).focus();
                            i += 1;
                        }
                        else{
                            $(".span"+tagid).remove();
                        }
                    }
                    //Validation for Radio End              
                    else{

                    }
                }
                //return false;
            }
            function Validate(){
               if(!validation()){
                    return false;
                }
                return true;
            }
            function onloadevents(){
                tags[tags.length -1].onclick = function(){
                    //return Validate();
                }
                for(var j=0;j<formtag.length;j++){
                    formtag[j].onsubmit = function(){
                        return Validate();
                    }
                }
                for(var i=0;i<tags.length;i++){
                    var tagid = tags[i].id;
                    var tagval = tags[i].value;
                    var tagtit = tags[i].title;
                    var tagclass = tags[i].className;
                    if((tags[i].type == "text") && (tagclass.indexOf('numeric') != -1)){
                        //enter class = numeric where you want to use numeric validator
                        document.getElementById(tagid).onkeypress = function(){
                            numeric(event);
                        }
                    }
                }
            }
            function numeric(event){
                var KeyBoardCode = (event.which) ? event.which : event.keyCode; 
                if (KeyBoardCode > 31 && (KeyBoardCode < 48 || KeyBoardCode > 57)){
                    event.preventDefault();
                    $(".spannum").remove();
                    //$(".numeric").after("<span class='spannum'>Numeric Keys Please</span>");
                    //$(".numeric").focus();
                    return false;
                }
                    $(".spannum").remove();
                    return true;
            }
            if (document.addEventListener) {
              document.addEventListener("DOMContentLoaded", onloadevents, false);
            }
            //window.onload = onloadevents;
        </script>
    </head>
    <body>
        <form method="post">
            <label for="fname">Test 1 : </label><input type="text" title="Test 1" id="fname" class="form1"><br>
            <label for="fname1">Test 2 : </label><input type="text" title="Test 2" id="fname1" class="form1 compare"><br>
            <label for="fname2">Test 3 : </label><input type="text" title="Test 3" id="fname2" class="form1 compare"><br>
            <label for="gender">Gender : </label>
            <input type="radio" title="Male" id="fname3" class="gender" name="gender" value="Male"><label for="gender">Male</label>
            <input type="radio" title="Female" id="fname4" class="gender" name="gender" value="Female"><label for="gender">Female</label><br>
            <label for="fname5">Mobile : </label><input type="text" title="Mobile" id="fname5" class="numeric"><br>
            <label for="fname6">Email : </label><input type="text" title="Email" id="fname6" class="email"><br>
            <input type="submit" id="sub" value="Submit">
        </form>
    </body>
</html>

回答by Roko C. Buljan

function hasValue( val ) { // Return true if text input is valid/ not-empty
    return val.replace(/\s+/, '').length; // boolean
}

For multiple elements you can pass inside your input elements loop their value into that function argument.

对于多个元素，您可以在输入元素内部传递它们的值到该函数参数中。

If a user inserted one or more spaces, thanks to the regex s+the function will return false.

如果用户插入一个或多个空格，多亏了正则表达式，s+该函数将返回 false。